FileWrite without overwite and remote location
"This doesn't seem to work." - What exactly is not working?
Please post all your three import statements: CreateFileA(), WriteFile() and Closehandle(). Probably the error is there. And I don't see a declaration of your variable "Buffer". Your 2nd last line should be
WriteFile(hFile, InfoToWrite, StringLength, BytesWritten, 0);FileLength (nNumberOfBytesToWrite) is needed because the function needs to know how many bytes to write, starting from the pointer lpBuffer.
BytesWritten (pNumberOfBytesWritten) is needed because *you* want to know how many bytes have been written. This can differ from nNumberOfBytesToWrite under some circumstances. In fact, it's the same value the MQL function FileWrite() returns.
Hi Paulepanke,
Let me start with posting the whole mql4 file that I'm currently working in.
Then, this does create a file and I was hoping to find the three strings in it. But I only see the last string ("Entry3"). I guess at every new entry it erases any previous data (if any exists). Does this have to do with lpBuffer and/or pNumberOfBytesWritten ? I think I have to make it start at a new line. Don't know how though.
#import "kernel32.dll" #define GENERIC_READ 0x80000000 #define GENERIC_WRITE 0x40000000 #define FILE_SHARE_READ 0x00000001 #define FILE_SHARE_WRITE 0x00000002 #define FILE_SHARE_DELETE 0x00000004 #define CREATE_NEW 1 #define CREATE_ALWAYS 2 #define OPEN_EXISTING 3 #define OPEN_ALWAYS 4 #define INVALID_HANDLE -1 int CreateFileA( string FileName, int DesiredAccess, int dwShareMode, int lpSecurityAttributes, int dwCreationDistribution, int dwFlagsAndAttributes, int hTemplateFile ); bool WriteFile( int hFile, string Buffer, int nNumberOfBytesToWrite, int lpNumberOfBytesWritten[], int lpOverlapped ); bool CloseHandle( int hObject ); int init() { return(0); } int deinit() { return(0); } int start() { WriteNewData("Entry1"); WriteNewData("Entry2"); WriteNewData("Entry3"); return(0); } void WriteNewData(string NewMessage){ string Location = "C:/test.CSV"; int hFile = CreateFileA(Location,GENERIC_WRITE,FILE_SHARE_READ,0,OPEN_ALWAYS,0,0); int FileLength = StringLen(NewMessage); int BytesWritten[]={0}; WriteFile(hFile,NewMessage,FileLength,BytesWritten,0); CloseHandle(hFile); }
Right, now it does. And everything at a new line. Is there a better way to make it automatically open a new line for a new string of text being added?
#import "kernel32.dll" #define GENERIC_READ 0x80000000 #define GENERIC_WRITE 0x40000000 #define FILE_SHARE_READ 0x00000001 #define FILE_SHARE_WRITE 0x00000002 #define FILE_SHARE_DELETE 0x00000004 #define CREATE_NEW 1 #define CREATE_ALWAYS 2 #define OPEN_EXISTING 3 #define OPEN_ALWAYS 4 #define INVALID_HANDLE -1 int CreateFileA( string FileName, int DesiredAccess, int dwShareMode, int lpSecurityAttributes, int dwCreationDistribution, int dwFlagsAndAttributes, int hTemplateFile ); bool WriteFile( int hFile, string Buffer, int nNumberOfBytesToWrite, int lpNumberOfBytesWritten[], int lpOverlapped ); bool CloseHandle( int hObject ); bool LZSeek( int hObject, int Number1, int Number2 ); int init() { start(); return(0); } int deinit() { return(0); } int start() { WriteNewData("Entry1,"); WriteNewData("\nEntry2,"); WriteNewData("\nEntry3,"); WriteNewData("\nEntry4,"); WriteNewData("\nEntry5,"); return(0); } void WriteNewData(string NewMessage){ string Location = "C:/test.CSV"; int hFile = CreateFileA(Location,GENERIC_WRITE,FILE_SHARE_READ,0,OPEN_ALWAYS,0,0); int FileLength = StringLen(NewMessage); int BytesWritten[]={0}; LZSeek(hFile,0,2); WriteFile(hFile,NewMessage,FileLength,BytesWritten,0); CloseHandle(hFile); }
_llseek(handle,0,2) will set the pointer at the end of the file.
What's wrong with the way you write text? A line of code for each line of text? I normally do this:
string text = "hello" int handle = CollectorOpenFile("C:\\mt4\\file.csv"); for(int i=0; i<blahblah; i++) { WriteFile(handle,text+"\n"); } CloseFile(handle);
The extra new line at the end of the file has never caused me any problems.
I'm no expert is that the right way to import the functions? Why are CreateFileA etc. outside the import tages? Mine (which I copy and pasted from another) looks like this:
// constants for function _lopen #define OF_READ 0 #define OF_WRITE 1 #define OF_READWRITE 2 #define OF_SHARE_COMPAT 3 #define OF_SHARE_DENY_NONE 4 #define OF_SHARE_DENY_READ 5 #define OF_SHARE_DENY_WRITE 6 #define OF_SHARE_EXCLUSIVE 7 #import "kernel32.dll" int _lopen (string path, int of); int _lcreat (string path, int attrib); int _llseek (int handle, int offset, int origin); int _lread (int handle, string buffer, int bytes); int _lwrite (int handle, string buffer, int bytes); int _lclose (int handle); int CreateDirectoryA(string path, int atrr[]); bool DeleteFileA(string lpFileName); void OutputDebugStringA(string msg); #import
and then the open, close, write and create folders functions look like this (maybe modified to my purpose, I can't remember):
//+------------------------------------------------------------------+ //| open file //+------------------------------------------------------------------+ int CollectorOpenFile (string path) { int result; int handle = _lopen(path,OF_WRITE); if(handle<0) //if couldn't open (no file / file already open) { handle = _lcreat(path,0); if(handle<0) //if couldn't create file -> create path { if(!CreateFullPath(path)) //if couldn't create path -> report big problem { Alert("1bidask_collector: Failed creating folders: ",path," exiting START. (is file already open??)"); return(-1); } handle = _lcreat(path,0); //if could create path -> create file }//end if(couldn't create file) result = _lclose(handle); handle = -1; }//end if(couldn't initially open file) if(handle < 0) //if couldn't initially open file { handle = _lopen(path,OF_WRITE); result = _llseek(handle,0,0);//pointer at start if(result<0) { return(-1); } } return(handle); } //+------------------------------------------------------------------+ //| close file //+------------------------------------------------------------------+ bool CloseFile(int &handle) { int result=_lclose(handle); if(result<0) { Alert("error closing file with handle:",handle,", exiting CollectorCloseFile..."); return(FALSE); } handle = -1; return(TRUE); } //+------------------------------------------------------------------+ //| write to file //+------------------------------------------------------------------+ bool WriteFile(int handle, string buffer) { int result = _llseek(handle,0,2);//pointer at end if(result<0) { Alert("1bidask_collector: (in CollectorWriteFile) Error placing the pointer to end of file, exiting WriteFile..."); return(FALSE); } int count = StringLen(buffer); if(count<1) { Alert("1bidask_collector: (in CollectorWriteFile) buffer size was:",count,", exiting WriteFile..."); return(FALSE); } result = _lwrite(handle,buffer,count); if(result<0) { Alert("1bidask_collector: error writing to file handle",handle," buffer sizë:",count," bytes, exiting WriteFile..."); return(FALSE); } return(TRUE); } //+------------------------------------------------------------------+ //| parse path: help make folders //+------------------------------------------------------------------+ bool ParsePath(string & folder[], string path) { bool res = false; int k = StringLen(path); if (k==0) return(res); k--; Print("Parse path=>", path); int folderNumber = 0; //---- int i = 0; while ( k >= 0 ) { int char = StringGetChar(path, k); if ( char == 92) // back slash "\" { if (StringGetChar(path, k-1)!= 92) { folderNumber++; ArrayResize(folder,folderNumber); folder[folderNumber-1] = StringSubstr(path,0,k); Print(folderNumber,":",folder[folderNumber-1]); } else break; } k--; } if (folderNumber>0) res = true; //---- return(res); } //+------------------------------------------------------------------+ //| create all folders //+------------------------------------------------------------------+ bool CreateFullPath(string path) { bool res = false; if (StringLen(path)==0) { Alert("1bidask_collector (CreateFullPath): tried ParsePath but length of path was 0"); return(false); } Print("Create path=>",path); //---- string folders[]; if (!ParsePath(folders, path)) { Alert("1bidask_collector (CreateFullPath): ParsePath failed"); return(false); } Print("Total subfolders:", ArraySize(folders)); int empty[]; int i = 0; while (CreateDirectoryA(folders[i],empty)==0) i++; Print("Create folder:",folders[i]); i--; while (i>=0) { CreateDirectoryA(folders[i],empty); Print("Created folder:",folders[i]); i--; } if (i<0) res = true; //---- return(res); }
and this works :)
Thanks Alladir, I've just inserted it in my code and it does work for me. However, the earlier mentioned code works too, I believe your code is more fail safe.
Now I have another question.
Say that I have 3 csv files File1.csv / File2.csv / File3.csv
The first column indexes the values where the second column gives the actual values. My goal is to match values by index from different files. If for the specific index there is no entry the values from a the nearest previous index should be taken.
For example if I want to match entry 103 then this would be
entry 103 value File1.csv 1986 / value File2.csv 1565 (entry 102 File2.csv) / value File3.csv 1752 (entry102 File3.csv)
Is there an option to jump directly to entries?
File1.csv 100 1029 103 1986 104 1674 105 1029 108 2388 109 2261 112 2448 113 1347 114 1462 116 1641 118 2337 119 1568 122 1894 125 1743 126 1530 127 1510 129 1216 130 1719 133 2099 135 1502 File2.csv 100 619 102 1565 104 1689 107 2302 110 2287 113 1276 116 1100 119 1996 122 1142 124 1641 127 1764 128 1529 129 2495 132 1239 134 1612 135 2500 136 892 137 798 140 1736 141 2252 File3.csv 100 1475 102 1753 105 738 108 1798 109 651 110 1512 112 2316 115 1977 117 1975 119 877 120 2042 123 832 124 2024 126 1657 129 1923 130 2193 133 2031 134 2413 137 1965 140 1209
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Hello,
I'm trying to write CSV files outside of the mt4/experts/files folder. This works. Now I'm trying to do add info to CSV files without overwriting previous info. This doesn't seem to work.
I'm not sure if the FileLenght and BytesWritten part is needed (I don't know what they do?) .
Basically I need this:
-Check if the CSV file exists. If yes open and go to last line and add the info there. If it doesn't exist yet, make it and go to last line (which is 0 at a new file) and add the info there.
Thanks!
FileName = "TEST.csv"; int hFile = CreateFileA(FileName,GENERIC_WRITE,FILE_SHARE_READ,0,OPEN_ALWAYS,0,0); string InfoToWrite = "Test123" int StringLength = StringLen(InfoToWrite); int BytesWritten[]={0}; WriteFile(hFile,Buffer,StringLength,BytesWritten,0); CloseHandle(hFile);